That Promises mistake everyone makes in JavaScirpt

http://stackoverflow.com/q/23803743/1348195

by inglor • 12 years ago

2 1 12 years ago

gren• 12 years ago

An other common mistake when you begin with promise:

    var result = promise.then(identity, function (error) { console.log(error); })

Oops, you just recovered your promise with undefined. result will always be successful. Yes if you don't throw again (or return a new failure promise) in your error callback it will make the resulting promise successful.

I haven't checked if this behaviour is the same on the DOM Promise API but it is on Q (which is the most popular JS lib for Promises).

That Promises mistake everyone makes in JavaScirpt

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